


Them

by Azurite9925



Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Alternate Universe, Cruel!Byleth, Demon God!Byleth, Easter Eggs Galore, F/F, F/M, Look this is why I'm not allowed to stay up past my bedtime, Nonbinary My Unit | Byleth, Sexual Tension, Shapeshifter!Byleth, The agarthans won and the Adrestian Empire has all of Fodelan under its grasp, it's definitely a time, mentions of blood and murder, minor mentions of politics, no beta we die like Glenn, nothing graphic though
Language: English
Status: Completed
Published: 2020-04-22
Updated: 2020-04-22
Packaged: 2021-03-02 04:15:24
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,509
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23789182
Author URL: https://archiveofourown.org/users/Azurite9925/pseuds/Azurite9925
Summary: Within Their domain, you do not turn your back to Them. They were the greatest power on this land. They were the heart and soul of the Adrestian Empire, the judge, jury, and executioner.And Edelgard was utterly fascinated with Them.(Alternate Universe, where the Agarthans won.) Inspired by Raikishi's The Fell Star Consumes.
Relationships: Edelgard von Hresvelg/My Unit | Byleth
Comments: 11
Kudos: 43





	Them

**Author's Note:**

  * For [Raikishi](https://archiveofourown.org/users/Raikishi/gifts).
  * Inspired by [The Fell Star Consumes](https://archiveofourown.org/works/23740012) by [Raikishi](https://archiveofourown.org/users/Raikishi/pseuds/Raikishi). 



_Within Their domain, you do not turn your back to Them._

It was a rule that was drilled into her before she could even speak it. The way her elder sister’s grip would almost bruise her in order to stop her wriggling in the Alter - the concerned glances, the perfect posture, the saturated silence - all of it. All of it taught her. They were not one you could turn your back to.

Even all her 9 siblings, a gaggle of energy on the best of days, were perfectly still during the dawn of the first of every month, lining the walls of the Alter as if they were the stained glass windows themselves. That was how every month began: Emperor Ionius IX stood by the right hand of Them, his 10 children lined the walls of the Alter, a display of great power that has quelled rebellions and united Adrestia for as long as anyone could possibly remember.

As she has grown, Edelgard had realized that it is not the proud stance of power as the ruling family who serves as the right hand for Them, but rather the smug haze of pride for Them, knowing that they were under the complete command of Them.

She couldn’t find it in herself to be truly resentful.

For although it was the morning, the Alter’s pitch deep indigo stone walls absorbed all the light that drifted in from the stained glass. All the light that remained came from the parallel rows of regal lavender eyes, watching each stranger with a myriad of emotions, and the two glittering sapphire orbs that pierced into the hearts of all who walked in. 

It was like clockwork, from there. 

Every month, precisely one minute after the final royal took their place, They entered the Alter. Some days They wore the figure of a rubenesque, green haired woman, who, when angry, turned into a great dragon. Some, the body of a little girl with jade hair, a sleepy expression who wielded the immeasurable power to control time at the very flick of Their fingertips. Others, the body of a man who was far too long, far too broad, and far too expressionless and far too powerful with the sword of bones They kept. There They were, one of many bodies, one of many voices, one of many forms, but an overwhelming aura.

And, of course, those mercurial sapphire eyes. They were unmistakable.

“Enter.”

With that word, the day began.

Merchants, nobles, beggars - it didn’t matter. One by one, they came to the Alter. One by one, wishes, sins, life stories spilled out their lips, lining the walls with secrets which could not leave the room. Each of them, watched silently by Them, were granted what they deserved. 

They are the Progenitor god. They are the beginning. They listened. Healed. Granted boons.

To some, They were also the end. 

_Byleth,_ whispered the most hidden tomes in her father’s library. _Byleth Eisener, the King of the Underworld, the Ashen Demon, the savior of the Agarthans._

Every month’s meeting ended with a single citizen of Adrestian blood dragged into the Alter in chains, blindfolded, gagged, and stripped bare, thrown onto the floor at the feet of Their god. 

A payment.

Sometime between ages 10 and 12, Edelgard had become fascinated with how the Alter remained perfectly unchained when drenched with so much blood. When she asked her father, King Ionius IX roughly told her to focus on her studies and abruptly moved her two siblings farther from Them during the very next moon.

They had noticed the change. They had smiled, eyes twinkling in amusement.

Edelgard had smiled back.

And ever since, indescribable things happened. 

Flowers appeared upon her pillow - gnarled things with spiked leaves and fiery flowers curling hungrily around each other, lustful for any shred of light, living longer than any flowers ever had the right to, when put into a vase and on the windowsill of her room. No matter how many times her elder sisters stole them in fits of jealousy, they reappeared on her pillow each time, just a tad bit darker shade of red.

Letters slipped under her door, the second day of every month, written patiently in an elegant, flowery script. Letters detailing the twisted roots of the Adrestian empire, the minute details of the human mind, the experiments which had driven Adrestia to a new age of technological revolution, centuries ago. Those nights, Edelgard cast her gaze into the abyss of her ceiling, body steady but mind raging underneath. When sleep finally recieved her, all she dreamt of were Their steady sapphires, steady through the twisting landscape of worlds she never knew.

A boy - Hubert - reappeared in court as the lone survivor from House Vestra, somehow surviving the fire that fell all his family many moons ago. It was impossible - “ _where had he been, all those years? How has he grown so proficient in black magic so quickly? Isn’t he still a mere boy?”_ \- Yet here he was, bowing before the Emperor, his features, his silver eyes, nearly unmistakable from the late Marquis Vestra. 

Mysteriously enough, he refused to serve any van Hresvelg, not even the crown prince, though it was in his blood as a Vestra. Any von Hresvelg, that is, except Emperor Ionius IX’ ninth child, the young princess Edelgard. 

Edelgard wasn’t quite sure what to do with him beyond requesting that he, with his very long arms, reach for the books she couldn’t quite yet get in the library. She had many words to look up and many books to review, in the wake of each letter. But soon, she grew accustomed to her newest shadow as well, appreciating the steadiness of his loyalty. It helped that she found his creativity with poisons endearing and endlessly fascinating, rather than fearful.

(They had merely glanced at Hubert, lip twitching, before promptly ignoring the newest guest in the Alter. Edelgard’s eyes softened as she watched the retreating figure of her God.)

She never did get used to the contemptuous glares her elder siblings sent her way, though.

But in due time, Edelgard had grown.

She had grown into the sharpness of her cheekbones, the stout strength of her bones, her deep brown hair fading and fading and fading until it stayed at the unnatural color of snow. She had grown into courtly words and political gestures, the delicate dealings of a spider. She had grown in her prowess of axes, her talent and fire unnatural even for a princess of royal blood, the strength of her dual major crests a fearsome sight for any who watched. 

All under the patient gaze of those sapphire orbs, seeking her lavender ones out, every single month, a slight smile curling the corner of Their lips.

Edelgard always smiled back. 

Upon cleaving the head off of her eldest brother with her most trusted silver axe, her father had merely stared deeply into those eyes that looked so much like his own, and declared her the empire’s heir.

“Congratulations, Heir Edelgard.” 

Of course, they had seen. Where else would a formal dual for succession be, except their Alter? Edelgard merely turned her head towards the shadowed God, bowing deeply and reverently, heart fluttering at the simple and polite phrase.

Footsteps echoed through the Alter.

A single, cold, dry finger pushed underneath her chin, the sharpened talon at the tip piercing the supple flesh of her neck, exposing a single drop of blood that Their hungry eyes followed down into the valley of her endowed breasts. Soon, They rested the pads of two fingers at the base of her throat, a slow, toothy smile spreading across Their face at the feeling of her rapid pulse.

“An excellent performance.” They commended, causing a quiver at the base of Edelgard’s spine. “You will grow excellently, but not here. Go, go to Garreg Mach Monastery. Go as my champion, dear princess, there is no one I’d rather trust for it.” The God purred, their other hand rising to gently stroke the silver stream of Edelgard’s hair. 

“Only for you, my lord.” she rasped, throat oh so suddenly dry. Unnoticed to the others, They had slipped a single momento into her pockets - _something light, something with a chain_ \- with something that Edelgard was not sure were fingers at all. 

It had ended both too quickly and too slowly for Edelgard’s tastes, after that. A single carriage of herself, Hubert, and a single guard set out at dusk, slowly leaving the familiar lights of Enbarr, winding their way to a grand white stone fortress upon a hill, in the very middle of the empire. Garrag Mach Monastery, the elite officer’s academy, hosted only the best youth of the empire. 

For over 300 years, no other von Hresvelg but the heir had attended.

When Edelgard stepped out from the carriage in menacing silver armor, still stained with the dried blood of her eldest brother and wearing a lock of his distinct charcoal hair around her neck, she reminded them that this tradition had yet to change.

Neither had the proud crimson flowers, who now grew unnaturally from the cracks of her floorboards, quietly wrapping themselves around the corners of her dorm room. Neither had the letters, each just as thoughtful and detailed as the last, slipped under her door. Neither had Hubert, who seemed to only improve in his ability to be her shadow.

And yet, everything had changed. 

When Edelgard returned to the imperial palace in Enbarr, all of one year wiser, all of one year stronger - silence had been her only receiver.

No longer did the giggles of her younger brother echo through the halls, the gentle ruffles of the skirts of her sisters, the steady steps of her father. No longer did the palace bustle with the generations of servants whose bones had been ground to dust in the depths of their devotion. No longer did the gardens bloom any other flower except the gleaming red flames which followed Edelgard wherever she went.

Her feet carried her to the Alter.

Her feet carried her to first, her old position - but then, with quiet realization, she strode to the very front of the room and stood beside the throne as she had seen her father do many moons ago, eyes staring straight ahead into the emptiness, fingers tightening around her torch, heart fortifying itself against the oppressive silence. 

“Excellent.” Cooed the very walls. 

Edelgard kept her gaze forward, still even when the doors opened with a measured grace, still even when sapphire locked into lavender, still at the echoes of every footstep 

Today They were what Edelgard believed was Their true form. The silver scales that trailed down the sides of Their neck and chest gleamed, casting an ethereal light to the halo of Their wild indigo hair and emphasizing the harshness of Their fangs and claws. They stepped so close to Edelgard, so close that her cheek could feel the gentle currents of the diety’s breathing. 

“Byleth.” Edelgard whispered, the name lingering in the air.

Sapphire eyes widened, and a deep laugh sending a tremor through Their sturdy chest, “Oh my… I haven’t heard that name in ages…” Byleth rumbled, leaning forward enough to gently press her oh-so-human nose against the sensitive skin just bellow Edelgard’s ear, each exhale sending shivers through Edelgard’s body.

“My lord… where is my family?” Edelgard asked.

Byleth wrapped her arms around the princess’ torso, claws teasing the ribbons that held Edelgard’s gown together. They nibbled gently at her ear, smirking at Edelgard’s gasp of surprise, seemingly paying no mind to Edelgard’s question. 

“B-byleth.” Edelgard tried again, mustering up all her strength. “Byleth, please, where is my father?” The diety paused Their ministrations, arching Their neck to meet Edelgard’s worried gaze. Sighing lightly, Byleth pulled away from Their latest prize, turning instead towards the rest of the room.

“My final courting present, one for each month we have been apart.”

A single snap of the fingers.

The windows glowed, flushing the entire room in light, revealing the near-perfect corpses of her family, upheld by the rigid vines of the crimson flowers, their eyes set steadily forward, yet idle, unseeing, like the most lifelike dolls Edelgard had coveted in her youth.

The Empress had covered her mouth, gloved fingers trembling, heart doused in ice water. She wrenched her eyes away from the horrific audience of her family and towards Byleth, who was watching her with curious eyes, a hungry smile curling Their lips. “Byleth…” Edelgard choked.

“Shh…” Byleth cooed, “Let me…”

Deftly, Byleth untangled the golden twin horns from the limp hair of Edelgard’s eldest sister, apathetically shaking a few stray brown hairs from the crown and turning towards Edelgard. The shadows around the Empress curled into her hair, deftly twisting it so that the grand golden crown, bestowed traditionally to the highest ranking female in the entire empire, could be woven into her very own silver locks.

Byleth’s claws were gentle, unnervingly so, in Their adornment.

Edelgard numbly watched Their movements, shuddering slightly at the featherlike touches of Byleth’s scales against the back of her neck. Edelgard let out a shuddering breath, eyes darting down to her hands.

Hands which were now cased in dried blood.

“Shh…” Byleth cooed once more, leaving little cuts upon the Empress’ porcelain skin with every tear They wiped away. “You have merely ascended, my dear Empress. Did you truly think Ionius had no other family through natural means?” Byleth murmured, cocking Their head.

Still, Edelgard’s eyes bore into her palms, her breathing erratic, mind hazing.

Byleth, seeing the Empress’ distress, gently led her to the dias, and, upon sitting on the throne Themselves, pulled Edelgard onto Their lap, shadows curling around the petite empress, two muscular arms wrapping themselves around her waist.

The silver hairs on the back of her neck stood erect, eyes widening as she lost sight of Byleth - Byleth, who was sitting _behind her back_. As if feeling her distress, Byleth rested Their chin on Edelgard’s shoulders, just far enough that Edelgard could see Them in the corners of her vision. Expression carefully blank, Byleth pressed Their nose against her throat once more, the gentle warmth of Their breath belying the menacing gleam of the rows of pearly teeth beneath them. 

_And then, like lightning_ -

“AH - ah…. Byleth?” A pained whimper accompanied the gentle patter of blood onto the stone floor, and Byleth smiled, pleased, Their long tongue gently drinking the blood that wept from Edelgard’s throat. A wave of exhaustion spread through the Empress’ tense muscles, loosening them against Byleth’s chest. Edelgard’s eyes unfocused, hooded as they gazed down at the arms that held her, wondering just when They had become so warm.

“Silly girl.” Byleth mused, fingers absently trailing down Edelgard’s body, almost curious in their ministrations, Their arms and fingers slowly turning pale and slender in a flattering mimicry of the guest on Their lap. “Silly, silly girl...” 

Byleth pressed a single kiss to the back of Edelgard’s head.

“You’re mine, now.”

**Author's Note:**

> Thank y'all for reading!
> 
> As I mentioned, this was vaguely inspired by Raikishi's The Fell Star Consumes, and while I could never capture their style of beautiful character chemistry, man do I love the concept of a demonic!creature!powerful!Byleth - though I've taken it definitely a little darker than they did. Thank you for your absolutely lovely fic, by the way, Raikishi!


End file.
